The rocks do not have to move but I do. I have connective tissue and muscles but to move efficiently the better I am in balance the least muscular effort will go to keep me upright. If I view the spine as balancing well fitted rocks any small perturbance has to be made up elsewhere. As with the rocks there can be a wide range of being off centered while being balanced overall. However at the point of interaction between a smaller rock below a larger heavier stone the range of error must be very tiny as opposed to a smaller rock on top of a larger rock.
Styloid process of temporal bone
I feel all the musculature on the anterior throat/jaw/face is not balanced between the left and right. I believe it is related to speech being (left cerebral hemisphere)right sided. I am wondering if slight imbalance at the atlas of the spine skull interaction would result in greater forces being balanced by the musculature further down the spine.
The bit between our teeth